


Number 21

by Alphinss



Category: Harry Potter - J. K. Rowling, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Adoption, Established Aizawa Shouta | Eraserhead/Yamada Hizashi | Present Mic, Father-Son Relationship, M/M, Oblivious, Parental Aizawa Shouta | Eraserhead, Protective Aizawa Shouta | Eraserhead, harry is adopted
Language: English
Status: Completed
Published: 2019-04-08
Updated: 2019-04-08
Packaged: 2020-01-06 19:11:18
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,298
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18394592
Author URL: https://archiveofourown.org/users/Alphinss/pseuds/Alphinss
Summary: There is a twenty first student in class 1A. Not that any of the students care. He tends to fall into the background. What they don’t know is that he is really the adopted son of their homeroom teacher. With a quirk none of them could hope to match.





	1. Chapter 1

**Author's Note:**

> Not sure what I'm going to do with this. I just had the idea in my head. May continue it. May not. Please enjoy.

Prologue:

Shotou Aizawa had never intended to have a son. Well, adopt one. But it was the same, wasn’t it? Either way he had to raise the boy. Yet that notion had never been part of the narrative that he had set out himself. A pro-hero, a teacher, a cat lover. Those had been things he was. A father was never one of those things. Not until it was.

A jumble of words. The commands of them seemed to be met instantly. As the villain had keeled over, his life ended from one syllable. ‘Death’. A heart that would never beat again. A small boy not really understanding what he had done.

Eraserhead had never seen another way forward. Adoption of the orphan was the only option. Harry was his son within the week.

That wasn’t to say that it was easy. Learning to control such an immense quirk. Learning a new language. Well, two really. Neither of those things had been simple. Present Mic had been there to help with that. But that didn’t mean that Shotou hadn’t been. Really he had been the only one who had ever had a chance to help the boy.

When his son had become frustrated. When green eyes flashed with anger. A word thrown across a room. Directed at the source. Shotou had been there to stop the word before it finished. He had been there to wrap the boy up in his arms. To sooth his violent sobs.

It took them a long time to work out Harry’s quirk. How it worked. What it really did. They really still were working it out. It seemed that whatever Harry said would happen. As with the villain. All it had taken was one word and the man’s heart had stopped.

But there seemed no way to control it. Intention had nothing to do with it. Harry could be talking about the weather and cause ice to form on the kitchen floor. He could be saying that he broke a lamp and a minute later all of the bulbs in the house were showering glass down on them.

A difficult decision. But to avoid anything more dangerous. To avoid potential fatalities, Harry’s voice would need to be silenced. It was how he came to learn his second new language; sign. It was the only real way for him to communicate without danger. It had been a safe choice.

Harry of course couldn’t go to a normal school. There was no way for him to be safe. No way to train his quirk which so desperately needed training. So when Aizawa accepted the job as a teacher at U.A. he did so only on the condition that his son be allowed to attend with him. No participation of course. Only watching. That hadn’t lasted long.

From the age of seven Harry had been a major part of the life of U.A.. Even if many didn’t know who he really was or the extent of his powers. He was always there. So when the new year of students were entering the school just as Harry turned fifteen. Well, it was the perfect opportunity for him to have a true high school experience.

 


	2. Chapter 2

 

There was a boy in their class. One that they found it hard to remember the name of. Was it Haruki or maybe Heiji? It was definitely an H. But the boy was easy to be forgotten. The one who seemed to just fall into the background without any complaints about it. He just wasn’t noticed.

At the Quirk Apprehension tests he hadn’t seemed to use anything other that his own physical abilities. Not a quirk in sight. But that had not meant that he had been last. Faster than Midoriya. Stronger than Iida. Jumping further than Shoji. He wasn’t bad. But neither did he stand out. He’d come, maybe, sixteenth or seventeenth. It was hard to remember. Just that he hadn’t come last. But he hadn’t stood out.

In classes he was the same. Just middle of the pack. Never a word to anyone. Sometimes he just seemed to disappear. No-one could really say if he had been in the class or not. It was possible he just skived all his classes. 1A just didn’t notice. However he seemed to do well in English. Not that anyone really cared about that. Academics were unimportant in the eyes of most class members. But on two occasions the twenty first member of their class had been seen listening to Present Mic. Nodding along to his rather rapid English.

Even the boy’s battle attire. Plain and unassuming. Black. All of it. Just as his hair was; falling to his shoulders. A scarf, similar to that of the erasure hero’s. The same material maybe? A potential training method? A fashion accessory? Hero worship? It didn’t matter. They’d never seen him use it.

“How did he even get into the school? He doesn’t do anything?”

“A rescue vote? Maybe he has a powerful relative?”

“He’s a little…well…freaky, don’t you think?”

It had been a conversation overheard. Between Sato and Sero. It seemed that afterwards the boy was even more of a shadow. If they had thought about him at all 1A may have wondered if he even attended classes anymore.

* * *

 

In the battle trials he had been with Shoto. Obviously overshadowed. He hadn’t done a thing. Their team had won within minutes. He had only just stood there. It had been unsurprising. Just as the boy was. Just there. Not standing out. Barely acknowledged. Even Hagakure stood out more and she was invisible.

As villains had invaded. As the security of U.A had been breached. The boys eyes had never left their homeroom teacher. Only ever looking as Eraserhead defended the students. Even as he was pulled through a warp gate; thrown as far away as possible. His eyes always seemed to be looking elsewhere.

As the villains poured in around them. He let the others take the lead. Shock blanket made. Villains electrocuted. He said nothing. A hand to help here and a shove of warning. Nothing else. Nothing special. Nothing.

The first sign that class 1A had of any emotion from the boy that they still couldn’t remember the name of was at their return to the school. Present Mic had approached him. His eyes with a twinkle of something. He took him to the side. Green eyes had widened. He had been gone in less than a second. Running down the corridor. They had wondered where. They had quickly forgotten about it.

The U.A sports festival had been next.

He’d made it into the top 42, although no one could really say how. Shoto had been sure he had been one of the students in the path of his ice. Minoru could have sworn that he had accidentally sent several of his balls in the boy’s direction. Midoriya thought he had seen one of the giant robots directly attack him. Yet he stood there, ready for the cavalry battle.

The boy had been on Shoto’s team. He moved as part of the group. Not standing out. Participating just as the others did. Securing himself a place in the final event. Hey only stood and watched as two of his classmates withdrew. His green eyes only looked. Not speaking a word.

His battle had been against Shinso. The other boy provoked the 1A student. Mocked him. Ridiculed him. Shouted at him. Yet he never said a word. The battle was over easily.

Yet, the results had many 1A students questioning. Had they ever actually heard their classmates voice? He never spoke in class. No teachers ever called on him. He had never introduced himself. He did have a tendency to be utterly silent. Was that something to do with his quirk? Or yet another thing that simply made him so unremarkable. They stopped thinking about it.

Their classmate’s next match had been against Tokoyami. The large black shadow had looked vindictive as it wrapped around its owner. The boy hadn’t looked even remotely interested in the match. In fact he had merely glanced up at the box where his homeroom teacher and English teacher were sitting. For one moment they were blessedly silent. Their twenty first member nodded. Some sort of unspoken message?

Then without even a blink he stepped out of the lines of the arena.

The match was over. It hadn’t even started. It had been seconds. Their classmate had forfeited the match. What useless sort of a hero was he? He had no right to be in their class. The rule of a hero; never give up.

* * *

 It seemed that there was one member of their class who always remained forgotten. One that was not part of them. One that either consciously or not, they all knew could never really be a hero. That was until they moved into their dorms.

Most members of the class didn’t even notice that the twenty first member of the class had joined them in their new living quarters. He had not participated in their room competitions. Had not shown off his cool new stab at interior design. Although if any of them had stopped to think about it, they would have guessed that he would have decorated exclusively in black.

It was Iida who had first noticed his appearance in the building. He had bumped into his one night. It had been late. Iida had needed a glass of water. His throat demanding it at three am. The warming of the weather wasn’t always appreciated.

As Iida had walked down the corridor to their kitchen, which also housed the communal space, he had heard voices. Well, a single voice. Questions being asked. Maybe the person was on the phone?

“You’re not even going to try?”

A pause.

“You can’t just…”

An interruption?

“Well, you shouldn’t then.”

Iida paused at the closed door.

“I could tell them”

Another pause. The perfect length for an answer.

“Well not everything, no. But something. Your training…”

Iida put a hand on the door handle and pushed gently. He really needed that water.

“Sorry to intrude” His voice was only above a whisper as he opened the door. “I just wanted to get some water.”

Iida’s eyes widened as he looked toward where the voices had originated. Sitting on the sofa that rested against one wall were two people. His homeroom teacher and the student that always seemed to be in the shadows.

Aizawa-Sensei was dressed in what were obviously pyjamas. Grey and black. The boy was dressed in his sports kit. The blue and white standing out against the dark couch. Had the two been talking? How? Iida had heard no responses from his classmate.

He realised he had been staring.

“Get your water Iida. Then go back to bed.”

Iida hurried to do as he was told. Quickly retreating to his room. He didn’t sleep.

* * *

 

The next person to notice their classmate’s presence was Midoriya. He had a question for Aizawa-Sensei. Wanted to know about their work experience. It was just after dinner when he knocked on the door of his teachers rooms.

“Come in” had been the muffled shout through the door. Midoryia did as asked.

Aizawa-Sensei looked tired. Sitting at a desk scattered with papers. Staring blankly at a document clasped between his fingers. He looked up. A small frown. He looked a little surprised to see Midoriya standing there before him. Midoriya shook it away. The man was simply an enigma.

“Sorry sir, I just wanted to ask about the work experience.”

The man’s face seemed to clear a little. “Right. What’s the problem?”

Midoriya had barely got through the first few lines of his explanation when the door once again opened. This time with no knock proceeding it. Aizawa looked up. Midoriya turned around.

Frozen in the doorway were two people. Present Mic; his hero uniform missing, but there was no mistaking that hair. Next to him was…Midoriya couldn’t remember his name. The twenty first member of their class. The outcast.

The boy seemed frozen. His hands in the air, as though signalling something. His eyes were wide.

It was Present Mic who broke the tension. “Oh, you’re busy Shouta? We just wanted to drop by and say hello. We can come back?” It was evident from his tone that he did not want to do that.

“No. It’s fine” Aizawa-Sensei cast a glance at Midoriya. “We’ll talk later Midoriya”

Midoriya was quickly shoved through the door, left to wonder what had just happened.

* * *

 

The next time the class noticed their twenty first member was when they had some visitors to the class. The big three, they had been called. The top three heroes in the school. Ones that would sure to be in the top ten pro-heroes in only a few years. They were not who the class had been expecting. That didn’t, however, stop their wish to train with them.

  
In the training grounds Amajiki only stood to the side, watching. The others were distracted by the battle they were engaged in. The whole class against one third year. One third year who soon had each and every one of them in a pile of limbs on the floor.

The students of 1A dazedly cast their glances around the room. Was anyone still left standing? Any chance at a win? There was Amajiki leaning against one wall. But who was there with him?

The unnoticed addition to their class was standing right by his side. It seemed that they were talking. Yet there were no words, at least from the boy. There were however responses from Amajiki. The mystery student’s hands were moving rapidly. The actions obviously translating into words for the number two student. There was a smile on his face and a nod of response.

The class of 1A could only stare. Soon all of their eyes glued to the pair. This was the most animated that they had ever seen their classmate look. He was talking with a third year, and by the look of it they knew each other quite well. Talking? Could it be called that? They were conversing at least.

However the habitually shy third year soon noticed the eyes on him. He did not appreciate the looks. His head was soon against the nearest wall. His back to the room. The conversation stopped as abruptly as the students had noticed it.

“Harry” Mirio was speaking. His voice calling over the students who had been felled by his quirk.

Harry? Who was Harry? The students looked around in confusion. There was only one person in the room that they didn’t know the name of. Harry? Was that really his name? It didn’t seem to fit.

The green eyes. Harry’s eyes, looked up. A small nod.

“You want in on this? You’re the only one left standing.” The number one hero was grinning madly at their classmate. The students of 1A had still not moved. From being frozen in pain to being frozen in utter confusion.

The boy, Harry, took a step forward. His hands made a few rapid movements. Mirio blushed.

“Right.” His voice sounded a little embarrassed. “But this won’t be the same as last time.”

A few quick jerks of fingers.

“Yes I’m sure. I’ve been training. Come on Harry” The last few words sounded more like a whine. Harry shrugged. Pointing at the members of his class. Then looking. up.

“Yeah, you’re right. But they can watch.” Mirio clapped his hands. “Okay 1A. Out the way. To the side of the room.” That seemed to snap the class out of their trance. They could only do as they were told. Even Bakugo was silent. All eyes were wide.

“Ready Harry?” Their classmate only nodded.

That appeared to be all that Mirio needed. His clothes were left in a puddle on the floor as he sunk into the concrete. Only to appear a second later behind their classmate. Harry seemed unfazed. He easily dogged the potential blow.

“Too easy” Mirio smiled. Faster. Dive after dive. He popped up in a seemingly random order of positions. But each was predicted. Harry dodging masterfully from each move. Faster still.

The scarf that they had never seen used, suddenly flared in their classmate’s hands. Movements so similar to their homeroom teachers. The boy was on the offensive now. Yet with each move of the scarf, limbs only sunk through it. With a grin from his opponent.

The students of 1A could only stare. What the hell? Was this really the same classmate that they had merely ignored and ridiculed. This was not the same boy. It couldn’t be!

“See Harry. Getting better.” Just as another strand of the black material slashed through his face.

Mirio suddenly became solid again. He grabbed harshly at the material. He tugged. Harry stumbled forward. Mirio was gone. He appeared a second later. His hands out. Ready to strike.

Harry whipped around.

“Freeze” One whispered word. It was a shout in the silence.

With one word the body of the third year student was just that; frozen. His whole body was stopped halfway through a jump. A position that no one would have naturally been able to hold. He really was frozen.

Green eyes blinked. A step back from the rather naked third year.

“Release”

The top hero in the school fell to the floor in a heap. A hand coming up to cover his modesty. His smile was wide as he looked up.

“At least I got you to use your quirk this time.”

Harry offered a hand, pulling the older student to his feet. He gave a nod. A smile. The moment was soon broken.

“What the fuck was that? How the hell did you even…What?!” A plume of fire erupted from the volatile Bakugo. “What!!”

Mirio looked over to the boy. Confused. “What do you mean?”

“I mean” Bakugo was yelling. “What the fuck was that?” His hands were moving wildly. Pointing at Harry in aggravation.

“It was fight? I did better than last time, might I add. I think Harry here was going a little easy on me.” The man patted their classmate on the back. Harry’s face was stone.

None of what he was saying was helping them. None of it making any sense.

“You fought before?” It was Uraraka speaking this time. Her voice much quieter than Bakugo’s.

Mirio only looked more confused. “Well of course. You know, in training? When Harry joins the third years on Thursdays. Not that any of us can beat him.”

The third year laughed, once again slapping Harry on the back. The black haired first year looked tense. However the eyes of all of the rest of 1A were wide. Their mouths agape. Mirio looked even more confused.

“Wait. His dad didn’t tell you?”

Iida finally got his bit in. He was class leader after all. He was here to sort out these kind of confusions. “Why would his father tell us? We wouldn’t even know who he was.”

If Mirio frowned anymore the look may become permanent. “What do you mean? Of course you would. He is your homeroom teacher after all.” A small confused smile.

What?

What?!

All eyes suddenly turned to the man who was standing in the corner. His eyes their tired red and his clothes far from neat. Aizawa-Sensei only raised an eyebrow. There was no denial in his eyes. Only acceptance. His son. The boy who had been in their class for the last six months. He was really the son of the pro-hero Eraserhead. Of their homeroom teacher.

What the hell was going on?!


End file.
